In a conventional motor control device, a duty of a current undetectable phase is fixed at 100% to prevent switching noise generated in a maximum phase where current detection is impossible from hindering current detection performed in relation to two phases other than the undetectable phase. Further, in this conventional motor control device, the phase current value of the undetectable phase is estimated on the basis of the phase current values of the two phases other than the undetectable phase (see PTL 1, for example).
Further, in a conventional frequency converter for an AC motor, a current detection zone is secured by adjusting an ON timing of a PWM pulse to the first half of a single PWM period, while a PWM output width is adjusted to the second half (see PTL 2, for example). By performing these adjustments, current detection precision and output can both be secured.